This invention relates to an improved high pressure fluid reciprocating pump. Pumps of this type are typically used in high pressure fluid delivery systems to create a high pressure water jet, as for cleaning. Examples of pumps for such service will be seen in U.S. Pat. No. 4,277,229 to Pacht and U.S. Pat. No. 3,811,801 to Buse et al. Reciprocating pumps of this type generally include a plurality of plungers and cylinders and develop pressures in excess of 10,000 psi frequently subjecting their parts to significant stresses and fatigue failure due to stress fluctuations. Accordingly, due to the severe service environment of high pressure pumps of this type, maintenance thereof may be frequently required, particularly to the pressure end of the pump. Therefore, minimizing stress concentration points along with ease of maintenance, durability of construction, are all exceedingly important in determining the overall service performance of high pressure pumps.
In the Buse et al reference mentioned above, an inline valve pump superficially suggestive of applicant's present overall arrangement is shown in that ease of maintenance is a consideration underlining its design. However, with all such high pressure pumps, a considerable amount of input energy is required and it is therefore highly desirable to also increase the efficiency of the pump as well as its ease of maintenance. As will be described below, the pump of the present invention has features which not only provide increased ease of maintenance over the prior art, but also substantially raise the volumetric efficiency of the pump to thereby reduce the necessary energy input for a given pressure and volume output.